Raul Castro has been acting head of state since 2006, when Mr. Castro temporarily handed him power to undergo surgery. It is unclear whether Raul will succeed Mr. Castro.

Amnesty International called on Cuba's new leaders to protect human rights. It also called for the release of all prisoners of conscience and new measures to uphold freedoms and judicial independence.

The rights group urged the international community to end policies that hurt Cubans' human rights, such as the U.S. economic embargo.

U.S. President George Bush said he hopes Mr. Castro's retirement will lead to a peaceful political transition in Cuba.

In Brussels, the European Union said it is willing to engage in a constructive political dialogue with Cuba. Ties between Havana and the EU were strained in 2003, after Cuba's arrest of 75 dissidents.

The leader of the Russian Communist Party in Moscow praised Mr. Castro as a fantastic political leader who raised the flag of freedom.

Expatriate Cubans in Miami's Little Havana community in the U.S. state of Florida showed mixed reactions to the Castro announcement this morning. Some motorists honked their horns, but there were no boisterous celebrations.

Some customers at coffee shops in Little Havana hailed the news as an important step forward, while others expressed doubt that Cuba's political climate would change.

In July 2006, the streets of Little Havana erupted into celebrations when Mr. Castro announced he was handing over power temporarily to Raul to undergo intestinal surgery.

Little Havana has the largest population of Cubans outside the island.

Western leaders are hailing news of Cuban President Fidel Castro's plans to retire as an opportunity for political change in the island nation.A spokesman for British Prime Minister Gordon Brown said Tuesday that Cuba now has a chance for a peaceful transition to democracy....